台灣黑熊生長過程中斷奶前時期Streptococcus sp. 44%為最主要之菌群，而斷奶後則變成是Clostridium sp. 為最主要之菌群，由原本18%增加為38%，Streptococcus sp. 則降至17%。相似性分析顯示斷奶前後明顯分成兩群，而斷奶後樣本之間相似度並無太大差異，相隔一年及半年後的樣本與原先樣本比較相似度也都達到70%以上，顯示台灣黑熊在發育成熟後腸道菌相就不易改變。
不同熊科動物腸道菌相組成分析中發現，台灣黑熊、阿拉斯加棕熊、馬來熊之間，菌相組成非常相似，都是以Steptococcus sp.、Enterococcus sp.、Escherichia sp.為主，但是大貓熊則是Pseudomonas sp.、Enterobacter sp.為主。
This experiment utilizes polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) to analyze the composition of the Taiwan Black Bear’s intestinal tract bacterial compositions during growth which was then compared the intestinal bacteria of other species of bears. Our efforts primarily focused on using Phortix 1D to find similarities in the V3 mutated nucleotide region on the PCR-DGGE gel. Molecular cloning was then utilized to obtain the exact composition of bacteria in the sample collected.
Pre-weaning, Streptococcus sp. is the primary bacterium species present in the Taiwan Black Bear’s intestines at 44% of total bacterium composition. But after weaning, Clostridium sp. becomes the primary bacterium present at 38% rising from 17%. Streptococcus sp. levels however drop from the original 44% to 17%. Similarity analyses indicate that the pre-weaning and post-weaning bacterial fauna are split drastically into two groups, whereas post-weaning bacterial compositions seem to stabilize. Similarity studies done six months and a year after weaning are 70% alike, suggesting that Taiwan Black Bear intestinal bacterial composition does not change easily after the fauna matures.
Comparisons between the Taiwan Black Bear and other members of the Ursidae family reveal that both Alaskan Brown Bears and Malaysian Bears share the same intestinal bacterial fauna as the Taiwan Black Bear which primarily consists of Streptococcus sp., Enterococcs sp., and Escherichia sp. On the other hand, the Panda’s intestinal bacteria are composed primarily of Pseudomonas sp. and Enterobacter sp.
The study done suggests that changes in intestinal bacterial compositions are primarily linked to the bear’s diets. Further research is required to determine whether the species of bear or phase of development affects the intestinal bacterial composition.